Production of divalent metal sulfonates



Jan. 21, 1947. J. c. SHOWALTER 3 PRODUCTION OF DIVALENT METAL SULFONATES Filed D80. 18, 1944 M I2 Selucflvo Solvent Ruffinom EXTRACTION Extract I'M l6 Sulfuric Acid SULFONAT'ON Green Sullonic Acid f- Oil and Sullonic Acid" 2| l9 l L 2o BLOW'NG Awasso 25 24 lsopropyl Alcohol EXTRACTION oil 25 Alcohol and SulfonicAcid 27 28 C Anhydrous Divalent NEUTRALlZATlON Metal Hydroxide Liqhl Hydrocarbon EXTRA-CH0" Alcohol and Excess Metal Hydroxide Lubricating CH 7 $5 36 35 K b DSTLLATION Llght Hydrocor on Divclcnl Matol S lfonolom IN VEN TOR.

hTTORMEY.

V Patented Jan. 21, 1947 F H C E ENT PRODUCTION OF DIVALENT METAL I SULFONATES Jere C. Showalter, Goose Creek, Tex., assignor to Standard Oil Development Company, a, corporation of Delaware 13 Claims.

The present invention is directed to the production of divalent metallic salts of sulfonic acids. More particularly, the present invention is directed to a method for treating naphthenic petroleum fractions to obtain divalent metallic salts of sulfonic acid therefrom and particularly sulfonic acid salts of alkaline earth metals.

It is known to the art to treat naphthenic petroleum fractions to obtain divalent metal salts of sulfonic acids therefrom. In the methods usually employed in the art to produce divalent metal salts of sulfonic acids, a relatively large number of steps are required to obtain the desired product.

It is an object of the present invention to produce substantially pure divalent metal salts of removed from the unit through line M will be sulfonic acids and particularly salts of the alkaa naphthenic petroleum distillate fraction to obtain an acid sludge including acid sludge bodies andgreen sulfonic acids and a sulfonated oil containing mahogany sulfonic acids, the treatment of the fraction including oil and mahogany sulfonic acids to separate sulfur dioxide therefrom and the extraction of the mahogany sulfonic acids by a solvent having the characteristics of aqueous isopropyl alcohol. The solution of mahogany sulfonic acids in the solvent is then neutralized by adding an anhydrous hydroxide of a divalent metal thereto to produce a mixture of metal sulfonates and excess metal hydroxide in.the solvent. The metal sulfonates are then separated from the solvent and excess metal hydroxide by adding light hydrocarbon thereto and settling under the influence of gravity. The solution of light hydrocarbon and metal sulforates is then subjected to a distillation step to evaporate the light hydrocarbon and leave substantially pure divalent metal sulfonate as product.

A preferred method for practicing the present invention will now be described in detail in conjunction with the drawing in which the sole figure is in the form of a diagrammatic flow sheet.

A distillate feed stock obtained by the fractional distillation of a naphthenic crude oil is passed via inlet ll into a solvent extraction unit l2 where it is contacted with a selective solvent under conditions to form a rafiinate fraction and an extract fraction. The step of solvent extraction with selective solvents is well known to the art and for this reason the operating conditions in unit l2 will not be described in detail. It may be stated that a selective solvent having the characteristics of phenol or furfnral is suitable for use in the solvent extraction step and that usually the extract will comprise approximately 35% of the volume of the original distillate and the rafiinate will comprise approximately 65% theresubstantially free from selective solvent.

The extract is withdrawn from solvent extraction unit I 2 via line It and sent to sulfonation unit IS. The step of sulfonating petroleum extracts is .in itself well known to the art. It is desirable to conduct this step by employing sulfuric acid of approximately 98% concentration and to treat the oil with a number of portions of the sulfuric acid with the withdrawal of acid sludge including acid sludge bodies and green sulfonic acids from the sulfonated oil after each application of sulfuric acid and before the succeeding batch of acid is added to the oil. In the drawing, the sulfuric acid employed in the sulfonation step is indicated as being added to sulfonation unit l5 through inlet It with the acid sludge being withdrawn through outlet H. The sulfonating step may advantageously be carried out with the naphthenic fraction and sulfuric acid initially at atmospheric temperature and the temperature allowed to increase as the reaction proceeds to a maximum within the range of to F.

The sulfonated oil fraction, including mahogany sulfonic acids, is withdrawn from unit l5 through line l8. It is preferred to pass the mixture of oil and mahogany sulfonic acids to unit H! where they are blown with air to insure the removal of sulfur dioxide therefrom, but as an alternative procedure, unit l9 may be bypassed. In the drawing, line I8 is provided with valve l8 and line20 provided with valve 20' so that by opening valve l8 and closing valve 20' the sulfonated oil mixture may be sent to unit I9, but, if it is desired to bypass unit 19, this may be done by closing valve l8 and opening valve 20'. In

- the drawing, air for blowing the mixture of oil and mahogany sulfonic acids in unit 19 is supplied through inlet line 2| and the mixture of air and sulfur dioxide i withdrawn from unitl9 through outlet 22.

The mixture of oil and mahogany sulfonic acids after having been freed from sulfur dioxide by blowing with air may be withdrawn from unit l9 through line 23 to extraction unit 24, or if the alternative procedure has been used and unit l9 bypassed, the mixture of oil and sulfonic acid passes through bypass line 20 and line 23 into extraction unit 24. In unit 24 a solvent having the characteristics of aqueous isopropyl alcohol is used to-separate the sulfonic acids from the oil. The solvent is brought into contact with the 3 mixture of mahogany sulfonic acids and oil and dissolves substantially all of the sulfonic acids therefrom but substantially none of the oil, and the solution of mahogany sulfonic acids in the solvent is subsequently readily separated from the oil under the influence of gravity. It is preferred to employ approximately 25 volume per cent of 50% aqueous isopropyl alcohol for washing the mahogany sulionic acids from the oil. In the drawing isopropyl alcohol has been shown as entering unit 25 through inlet line 26 and oil being withdrawn from unit 24 through outlet 26.

The solution of solvent and mahogany sulfonic acids is passed from extraction unit 24 through line 21 to unit 26 where it is neutralized by adding anhydrous divalent metal hydroxide thereto. In the drawing, the dry divalent metal hydroxide is indicated as being added to unit 28 through inlet line 29. In commercial operations it will usually be found desirable to employ dry calcium hydroxide as the divalent metal hydroxide employed to neutralize the mahogany sulfonic acids. It will be understood, however, that other anhydrous divalent metal hydroxides may be employed for neutralizing the sulfonic acids. A number of hydroxides are available for use as the anhydrous divalent metal hydroxide neutralizing the mahogany sulfonic acids; as examples, hydroxides from the metals of group II 01 the periodic table,

such as zinc, magnesium and the alkaline earth metals, calcium strontium and barium, aswell as other divalent metal hydroxides, such as lead hydroxide and zinc hydroxide, may be mentioned. However, in commercial operations it will usually be found desirable to use anhydrous hydroxides of the alkaline earth metals and particularly calcium hydroxide to neutralize the mahogany sulfonates.

It is desirable to add an excess of the anhydrous hydroxide of divalent metal and, accordingly, the mixture withdrawn from unit 28 through line 30 will usually include a substantial amount of excess divalent metal hydroxide in addition to alcohol, water and divalent metal sulfonates. This mixture passes from unit 28 through line 30 to unit 3| where it is extracted with a light hydrocarbon supplied to unit 3| through inlet line 32. Upon the addition of the light hydrocarbon to the mixture, sulionates are dissolved therein and the alcohol and excess metal hydroxide separated therefrom. The separation of the solution of sulfonates in the light hydrocarbon from the remainder may conveniently be carried out by settling under the influence of gravity. The fraction including alcohol and excess metal hydroxide may be withdrawn from unit 3| by outlet 33 while the solution of sulfonates' in the light hydrocarbon constituting the other fraction may be withdrawn through line 34. Hexane may conveniently be employed as the light hydrocarbon in unit 3|, but other hydrocarbons having similar characteristics and including propane, butane, pentane and heptane or mixtures thereof of these hydrocarbons may be used for this purpose.

The solution of divalent metal sulfonates in the light hydrocarbon passes through line 34 to distillation unit 35 and is distilled. The light hydrocarbon is removed as an overhead fraction and is withdrawn through outlet line 36. Th remaining fraction may be withdrawn as a bottoms through outlet line 31 and is substantially pure dry divalent metal sulfonate. The divalent metal sulfonates withdrawn from the still may be allowed to cool and harden and subsequently ground to obtain product in a desired commercial form.

If the divalent metal sulionate is to be employed as a motor oil additive, it may be desirable to add a petroleum fraction of suitable boilin range and viscosity, as in the range suitable for lubricating oil in internal combustion motors, to the solution flowing through line at to distillation unit 35. To this end line 33 controlled by valve 33' is provided by way of which the petroleum oil or other carrying agent may be introduced. It is understood that when oil is introduced into the solution of light hydrocarbons and divalent metal sulfonatc, the product withdrawn by line 31 will be in the form of a solution in the heavy hydrocarbon. I

The following is given as'an example illustrating a method for practicing the present invention when employing calcium hydroxide as the divalent metal hydroxide to produce substantially pure calcium sulionates.

Example An extract is obtained by extracting with phenol a.Coastal distillate having a viscosity of 200 Saybolt seconds at F. The resulting extract is treated with seven applications of sulfuric acid using 40 pounds of 98% sulfuric acid for each application and withdrawing the acid sludge including acid sludge bodies and green sulfonic acids from the sulfonated oil after each application. The sulfonated oil obtained by this acid treatment contains approximately 10% by volume of mahogany sulfonic acids and is blown with air to remove sulfur dioxide therefrom. After airblowing, the mixture of oil and mahogany sulfonic acids is brought into contact with 30 volume per cent of a 40% aqueous isopropyl alcohol and the 'sulfonic acids are thereupon dissolved in the alcohol. The solution of sulfonic acids in alcohol is separated from the oil by gravity separation and is then titrated for acidity. The theoretical amount of calcium hydroxide required to react with the sulfonic acids plus a 10% excess is added to the solution for neutralizing the sulfonic acids and one hour is allowed for the reaction to go to completion. One volume of hexane per volume of alcohol solution is then added to the solution of neutralized sulfonic acid, the mixture agitated violently and then allowed to stand for 24 hours. The calcium sulfonates dissolve in the hexane and upon settling form a top layer which is withdrawn from the remaining bottom layer including alcohol and excess calcium hydroxide. The top layer is distilled to evaporate the hexane and the remaining calcium sulfonates are withdrawn as product. The product is substantially pure dry calcium sulfonate having a molecular weight of 909 and is finished as a commercial product by cooling to harden it and then grinding to a fine powder which is white.

Having fully described and illustrated the practice of the present invention, what I desire to claim is:

1. A method for producing metallic salts of sulfonic acids including the steps of treating a naphthenic petroleum fraction with a sulfonating agent under conditions to produce an acid sludge including acid sludge bodies and green sulfonic acids and a mixture of oil and mahogany sulfonic acids, separating the mixture of oil and mahogany acids from the acid sludge by settling, extracting the mixture of oil and mahogany sulfonic acids with a solvent to form a solution of mahogany sulfonic acids in the solvent, separating the resultant solution from the remaining oil by settling,

} neutralizing the mahogany sulfonic acids in said hogany sulfonic acirb to produce divalent metal sulfonate and subsequently recovering the divalent metal sulfonate from the remainder of the solution by extracting them therefrom with liquid hydrocarbon solvent.

2. .A method for producing metallic salts of sulfonic acids including the steps of treating a naphthenic petroleum fraction with a sulfonating agent under conditions to produce an acid sludge including acid sludge bodies and green sulfonic acids and a mixture of oil and mahogany sulfonic acids, separating the mixture of oil and mahogany acids from the acid sludge by settling, extracting the mixture of oil and mahogany sulfonic acids with a solvent to form a, solution of mahogany sulfonic acids in the solvent, separating the resultant solution from the remaining oil by settling, neutralizing the mahogany sulfonic acids in said solution by the addition thereto of a divalent metal hydroxide capable of reacting with the mahognay sulfonic acids to produce divalent metal sulfonates, subsequently adding a'low molecular weight liquid hydrocarbon thereto to dissolve the divalent metal sulfonates in the light hydrocarbon, withdrawing the solution of divalent metal sulfonates in light hydrocarbon and evaporating the light hydrocarbon to recover substantially pure divalent metal sulfonates.

3. A method in accordance with claim 2 in which the divalent metal hydroxide is an alkaline earth metal hydroxide.

4. A method in accordance withclaim 2 in which the divalent metal hydroxide is calcium naphthenic distillate to a solvent extracting step with approximately 98% sulfuric acid under sulfonating conditions to produce an acid sludge including acid .sludge bodies and green sulfonic acids and a mixture of oil and mahogany-type sulfonic acids, removing the acid sludge component, blowing the mixture of oil and mahogany sulfonic acids with air to remove sulfur dioxide therefrom, subsequently extracting the mixture of oil and mahogany sulfonic acids with aqueous isopropyl alcohol to dissolve the mahogany sulfonic acids, withdrawing the solution of isopropyl alcohol and mahogany sulfonic acids from the oil, adding an anhydrous divalent metal hydroxide to the solution of mahogany sulfonic acids and alcohol to neutralize the mahogany sulfonic acids and produce divalent metal sulfonates, adding a low molecular weight liquid naphthenic petroleum fraction with a sulfonat- .sulfonic acids with a solvent to form a solution of mahogany sulfonic acids in the solvent, separating the resultant solution from the remaining oil by settling, neutralizing the mahogany sulfonic acids in said solution by the addition thereto of a. divalent metal hydroxide capable of reacting with the mahogany sulfonic acids to produce divalent metal sulfonates, subsequently adding a low molecular weight liquid hydrocarbon thereto to dissolve the divalent metal sulfonates in the light hydrocarbon, withdrawing the solution of divalent metal sulfonates in light hydrocarbons, adding a petroleum fraction in the lubricating'oil boiling range theretoand subsequently evaporating the light hydrocarbon to recover a solution of substantially pure divalent metal sulfonates in the petroleum fraction.

6. A method in accordance with clam in which the divalent metal hydroxide is an alkaline earth metal hydroxide.

7. A method in accordance with claim 5 in which the divalent metal hydroxide is a'calcium hydroxide.

8. A method for obtaining metal sulfonates including the steps of contacting a petroleum fraction obtained as the extract when subjecting a hydrocarbon thereto to dissolve the divalent metal sulfonates and withdrawing the solution of divalent metal sulfonates in low molecular weight hydrocarbon from the remainder, subsequently evaporating the low molecular weight hydrocarbon to recover substantially pure divalent metal sulfonates.

9. A method in accordance with claim 8 in which an alkaline earth metal hydroxide is employed to neutralize the mahogany sulfonic acids.

10. A method in accordance with claim 8 in t which anhydrous calcium hydroxide is employed to neutralize the mahogany sulfonic acids.

11. A method for producing metal sulfonates including the steps of sulfonating a feed stock obtained as the extract by solvent extracting a naphthenic petroleum distillate fraction with 98% sulfuricracid in the range of 250 to 400 pounds of acid per barrel of feed stock to form an acid sludge including acid sludge bodies and green sulfonic acids and a mixture of oil and sulfonic acids, separating the acid sludge from the mixture of oil and mahogany sulfonic acids, blowing the mixture of mahogany sulfonic acids and oil with air to remove sulfur dioxide therefrom, subsequently mixing aqueous isopropyl alcohol with the mixture of oil and mahogany sulfonic acids and settling to separatean oil layer and a layer of mahogany sulfonic acids dissolved in the aqueous isopropyl alcohol, withdrawing the layer of mahogany sulfonic acids dissolved in isopropyl alcohol and adding anhydrous divalent metal hydroxide thereto in an excess amount over that required to neutralize completely the mahogany sulfonic acids to form divalent metal sulfonates, subsequently adding a low molecular sulfonates.

13. A method in accordance with claim 11 in which calcium hydroxide is employed to neutralize the mahogany sulfonates.

' JERE C. SHOWAL'I'ER. 

